How could something as big as a Boeing 777 seemingly vanish into thin air. For the past five day, an international search to co-late the missing Malaysia airlines plane with 239 onboard has yielded no clues for loved ones desperate for information. With few facts, lots of theories are popping up, as ABC's senior national correspondent reports. Reporter: How could a plan larger than this 767 crash into the sea and leave no trace? Even as these grainy satellite images leased today by the Chinese government show what could be debris, there is still no proof. An open sea mystery that has seasoned aviators puzzled. David sus zi has been investigating plane accidents for 25 years. There's something very unique going on here that I haven't experienced in my investigations before. Reporter: On Reddit, everything from ailian abduction to a Chinese military power play is trending. But some of the less wild conspiracies actually warrant examination. Some of the theories that are being put forward, you have to think yeah, that needs to be looked into. Hijacking, for example. Could flight mh-370 been taken over? Radios and transponders silenced as it was flown to a nearby island. Eerily, families continue to call that you are lived ones cell phones, which because the call is international rings hauntingly before going to e-mail. Some say what's going on here is almost like the TV show "Lost." I think there's something that happened to this aircraft, whether or not they could have lappeded that aircraft in that region I find highly unlikely. Another prominent theory involves the military. Was it blown to small pieces by a rogue missile? Making the debris field too small to find? I don't see evidence of that whatsoever. The whole profile would have been much different than what we see today. We would have seen debris across the ocean. It would have spread as much as a mile across the ocean. Others wonder about secret military experiments gone awry. Developing star trek-like abilities. Cloaking. It is true military contractors are working on the possibility. Sounds space age to me. It doesn't surprise you that we hear all these? Oh, it would surprise me if you didn't. Yeah, this is what happens. And the longer it goes on, the crazier it's going to get. Another reason to find that plane, or what is left of it. For "Nightline," I'm Jim Avila in Washington.

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